UV lights reduce TB spread

Scientists using guinea pigs have shown that installing UV lights could reduce the transmission of TB (tuberculosis) in hospital wards. TB, a bacterial infection, is spread from person to person through droplets in the air when they cough. TB spread in hospitals is worsening as drug resistant strains become more common.

Researchers investigated the potential of UV light (to damage the bacteria’s DNA) and negative ionisers (a way of ‘cleaning’ the air) to reduce TB infection rates in hospitals. They pumped air from TB infected wards into three separate enclosures containing guinea pigs. The first group received air exposed to UV light in the ward, the second, air treated with negative ionisers, and the final group received untreated air.

The results were significant. A third of the group exposed to untreated air got infected with TB, compared with one seventh receiving ionised air, and less than one tenth of the animals exposed to UV-treated air. Effective ventilation systems increased the impact of UV treatment by directing the treated air downwards and the potentially infected air upwards. The scientists therefore recommended that the lights be used in combination with fans.

Plans are already underway to set up UV lights in a hospital in the UK. The chest clinic at St Mary’s Hospital, London, will be the first hospital to install this relatively low-cost solution.